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- The Climates of Earth’s next Supercontinent: Effects of Tectonics, Rotation rate & Insolation NASA Goddard Institute for Space Studies EGU2020 M.J. Way (NASA/GISS)1,2, H. S. Davies3 (NASA/GSFC), Joao Duarte3 (NASA/LARC) & J.A.M. Green4 (Bangor/Wales) 1 Goddard Space Flight Center, Sellers Exoplanet Environments Collaboration (SEEC) : 2 Dept of Physics & Astronomy, Uppsala Univ., Sweden : 3 Instituto Dom Luiz, Faculdad de Ciencias, Univ de Lisboa, Lisbon, Portual: 4 School of Ocean Sciences. Bangor Univ., Menai Bridge, UK Abstract GCM Model Setup We investigate two possible deep future Earth climate scenarios Conclusions 3-D General Circulation Model : ROCKE-3D (Way et al. 2017) using a 3-D GCM [1], 200 and 250 million years into the future Aurica: Mean surface temperatures for all simulations with Model Resolution: Atmosphere: 4º x 5º x 40 (latitude x longitude x layers), Ocean: 4º x 5º x 32 layers when the next supercontinent phase is expected to take place. large low latitude supercontinent are within 0.1 C. Topographies: Modern Earth, Aurica & Amasia (Future Earth Supercontinents) We use knowledge of the evolution of plate tectonics, solar Amasia: Mean surface temperatures span a range of 3 degrees Land: Albedo = 0.2 At Model Start (AMS), No land ice AMS, No vegetation, 50/50 = clay/sand soil with lowest mean surface temperature of 17.2 C due to large luminosity, and rotation rate over this time period. In one Oceans: Fully coupled (dynamic), contiguous ice sheets in northern hemisphere. This is because, scenario, a supercontinent forms at low latitudes. In the other Orbital Parameters: Modern Earth orbital period, day length = 24.5 hrs, Insolation: 1.025 x Modern unlike modern Earth, the oceans cannot transport sufficient heat scenario it forms at high northerly latitudes with an Antarctic Atmospheres: 1.) N2 dominated 1 bar, O2=21%, CO2=285ppmv, CH4=0.79ppmv, N2O=0.3ppmv from equatorial regions to higher northern latitudes. subcontinent remaining at the south pole. The climates differences between these two scenarios are dramatic, with differences in mean surface temperatures approaching 4 Topographies (Future Supercontinents in dark gray Modern outlined black) degrees. The fractional habitability (where mean surface temperatures are between 0

References: [1]Way et al. 2017 ApJS, 231, 12, doi: 10.3847/1538- 4365/aa7a06 [2] https://doi.org/10.1002/essoar.10501348.1 4 5 6

Summary list of simulations and results

SIM Sun 79% N2, 21%O2 Topography Runtime Tsurf CO2/CH4/N2O (years) (C) 01 Aurica Control 285/.79/0.3ppmv Aurica 2000 20.5

02 Aurica PD 285/.79/0.3ppmv “ 2500 20.6 Results: Snow & Ice Coverage in black, Continental outlines in red

03 Aurica 250f 285/.79/0.3ppmv “ 2000 20.6

04 Amasia Control 285/.79/0.3ppmv Amasia 2567 19.7 2 5 7

05 Amasia PD 285/.79/0.3ppmv “ 3000 17.2

06 Amasia 200f 285/.79/0.3ppmv “ 3000 20.2

07 Modern Earth 285/.79/0.3ppmv Modern 1000 14.2 No O3 nor Aerosols Earth

Future Continent Descriptions 2 5 7 Aurica is a Low Latitude Supercontinent 250 million years into the future Control= Low mean topography, land close to sea level, no mountains PD = Higher mean topography, land close to present day (PD) topography, no mountains 250f = Low mean topography with mountains

Amasia has a northern Supercontinent and most of present day Antarctica 200 million years into the future Control= Low mean topography, land close to sea level, no mountains PD = Higher mean topography, land close to present day (PD) topography, no mountains Acknowledgements: This research was supported by The NASA Astrobiology Program through the Nexus for Exoplanet System Science (NExSS) research coordination network, sponsored by NASA’s Science Mission Directorate; the Sellers 200f = Low mean topography with mountains Exoplanet Environments Collaboration (SEEC) at NASA Goddard Space Flight Center; The NASA Habitable Worlds Program, and the NASA High-End Computing (HEC) Program through the NASA Center for Climate Simulation (NCCS) at Goddard Space Flight Center.